US5190547A

Movatterモバイル変換

Info

Publication number: US5190547A
Application number: US07/883,685
Authority: US
Inventors: Forest C. Barber, Jr.; Durrell G. Tidwell
Original assignee: Midas Rex Pneumatic Tools Inc
Current assignee: Midas Rex LP
Priority date: 1992-05-15
Filing date: 1992-05-15
Publication date: 1993-03-02
Anticipated expiration: 2012-05-15

Abstract

A device for resecting a bone utilizes a pattern to control the cutting tip for the resection. The device has a frame with a pattern holder and a bone holder. A tool holder mounts to the frame by means of a four bar linkage assembly. The tool holder has a cutting tool and a probe mounted to it. The four bar linkage allows three-dimensional movement of the tool holder, but constrains the tool holder to always be in parallel with a line extending through the pattern holder and bone holder.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

This invention relates in general to equipment for resecting bones during implant and prosthetic surgery so as to match a pattern.

2. Description of the Prior Art

During certain types of orthopedic surgery, there is a need to cut or resect away part of the bone to a desired shape. For example, in the case of grafting a donor bone section to replace a diseased bone section, portions of the donor bone joint must be shaped to resemble the diseased bone joint as much as possible.

As another example, a tibial plateau prosthesis may be implanted in the leg of a user while retaining an existing femur. In that case, the existing femur must be resected to match the tibial plateau of the prosthesis as much as possible.

In the prior art, this is handled using high speed bone cutting or resecting equipment. A surgeon primarily relies on a visual comparison and skillful use of the equipment. The surgeon may also make molds to assist in performing the resection.

SUMMARY OF THE INVENTION

In this invention, a replicator apparatus for resecting the bone into a desired shape is provided that will precisely shape the bone to the pattern. The replicator includes a frame with a pattern holder and a bone holder. The pattern holder and the bone holder are spaced apart from each other on an X-axis, or bone-pattern axis. A tool holder holds a probe and a power cutting tool. The tips of the probe and the cutting tool are mounted on a line that is parallel to the tool holder axis.

A linkage means connects the tool holder with structure mounted to the frame. The linkage means comprises two pairs of parallel bars, each forming parallelograms. These bars are pivotally mounted so as to allow free movement in three dimensions of the tool holder. However, the bars will always maintain the tool holder parallel to the bone-pattern axis. The user traces the tip of the probe over the pattern while operating the cutting tool to shape the bone to match the pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a first embodiment of a replicator apparatus constructed in accordance with this invention.

FIG. 2 is a side view of the replicator of FIG. 1.

FIG. 3 is a front view of a portion of the replicator of FIG. 1.

FIG. 4 is a perspective view illustrating a second embodiment of a replicator apparatus constructed in accordance with this invention.

FIG. 5 is a perspective view of a third embodiment of a replicator apparatus constructed in accordance with this invention.

FIG. 6 is a perspective view of the bone holder and pattern holder of the replicator of FIG. 5.

FIG. 7 is a perspective view of the bone holder of the replicator of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, replicator 11 is constructed to be utilized in an operating room during surgery. Resecting replicator 11 has an L-shaped frame 13 which mounts to avertical rod 12.Frame 13 has a horizontal or X-axis portion 13a, extending along an X-axis 14 and a vertical or Y-axis portion 13b, extending along a Y-axis 16. A bone holder means 15 having an axis perpendicular to X-axis 14 is mounted toframe 13. Bone holder 15 is a circular rotatable plate that has three screw clamps 17. Screw clamps 17 are spaced 120 degrees apart from each other for tightening against a section of abone 19. In the embodiment of FIGS. 1-3,bone 19 will be a section of a donor bone for implanting in a human body. For example,bone 19 may be a femur of a knee joint. Preferably, bone holder 15 can be rotated relative toframe 13 about the axis of bone holder 15.

Apattern holder 21 is spaced from bone holder 15 along the X-axis 14.Pattern holder 21 is also a plate, having threescrew clamps 23 for clamping apattern 25. The axis ofpattern holder 21 will be perpendicular to and intersecting X-axis 14. In the embodiment of FIGS. 1-3,pattern 25 will be a mold formed by the surgeon during surgery.

Aclevis 29 mounts to the lower end of the framevertical portion 13b.Clevis 29 mounts to a pair ofshafts 31, as illustrated also in FIG. 2. Clevis 29 is not rotatable relative toframe 13. A threadedrod 33 having acrank handle 35, will moveclevis 29 forward and away fromframe 13Shafts 31 extend along a Z-axis which is perpendicular to X-axis 14 and also to Y-axis 16. A vertical line along the Y-axis 16 passing throughshafts 31 would pass through the center ofpattern 25.

Clevis 29 includes arotatable clevis bracket 37.Clevis bracket 37 is secured by apin 39 to spaced apart lobes ofclevis 29.Pin 39 is mounted along a clevis axis that is parallel to X-axis 14 and perpendicular toshafts 31.Pin 39 allowsclevis bracket 37 to swing in a Z-axis plane.

A pair of frameparallel bars 41 pivotally mount toclevis bracket 37. Frameparallel bars 41 are identical in length and size and mounted so as to always be parallel to each other. Frameparallel bars 41 each have a frame end mounted pivotally to clevisbracket 37 by spaced apart clevis bracket pivot pins 43. Pivot pins 43 are spaced apart from each other along the Y-axis 16. Pivot pins 43 allow rotation of frameparallel bars 41 in a plane containing frameparallel bars 41.

The opposite ends, or plate ends, of frameparallel bars 41 connect to alinkage plate 45.Plate 45 is free floating and has four pivotal pins, referred to herein as a zero degree pin 47, a 90degree pin 49, a 180degree pin 51, and 270degree pin 53. The zero degree pin 47 and the 180degree pin 51 Will always be located on a line parallel to a plane containing Y-axis 16. The 90degree pin 49 and 270degree pin 53 will always be located on a line parallel to X-axis 14. The frameparallel bars 41 connect to the zero degree pin 47 and 180degree pin 51. In the embodiment shown, the ends of the frameparallel bars 41 are located on the side ofplate 45 that facesframe 13.

A pair of tool holderparallel bars 55 have plate ends that connects to the 90degree pin 49 and 270degree pin 53. Tool holderparallel bars 55 are of identical length and are maintained always in parallel relationship to each other. The ends of tool holderparallel bars 55 are located on a side ofplate 45 that faces away fromframe 13.

The opposite ends of tool holderparallel bars 55 pivotally connect to tool holder pivot pins 57 of atool holder 59. The distance between pivot pins 57 is the same as the distance between pivot pins 49 and 53. Similarly, this distance is the same as between pivot pins 47, 51 and the pivot pins 43.Tool holder 59 includes atool holder sleeve 61 which supports pivot pins 57. Anextension member 63 extends completely throughtool holder sleeve 61.Extension member 63 extends on opposite sides ofsleeve 61 and is rotatable relative tosleeve 61. A tool holder axis extends alongextension member 63. The tool holder axis is maintained by the

parallel bars

41, 55 in a parallel relationship to X-axis 14 at all times.

A stylus or probe 65 mounts to the right side ofextension sleeve 61.Probe 65 is frictionally held in a hole extending throughextension member 63.Probe 65 has a tip 67 that will trace over the contour ofpattern 25. The tip 67 will be placed such that when touching thepattern 25, theclevis bracket 37 will be in a near vertical orientation.

Cuttingtool 69 is secured in a hole provided inextension member 63 on the opposite side ofsleeve 61. Cuttingtool 69 is a conventional high speed pneumatic cutting instrument. Cuttingtool 69 has a tip 71 that will contain a bit or other type of cutting tool for resecting thebone 19. Tip 71 is spaced apart from tip 67 the same distance as from the centerline of bone holder 15 to the centerline ofpattern holder 21. Also, probe tip 67 will be positioned so that a line passing through tips 67, 71 will be parallel with the axis oftool holder 59 and also parallel with X-axis 14. Anair hose 73 applies air pressure to cuttingtool 69 to form the cutting action.

In the operation of the embodiments of FIGS. 1-3, the surgeon will make a mold to form apattern 25. This may be done by first cutting the diseased bone from the patient, then pressing a moldable material against the cut area in the patient. The material will harden intopattern 25, which is then placed inpattern holder 21. The surgeon takes thedonor bone 19 and places it in bone holder 15. The surgeon will align the tips 67, 71 parallel with the axis oftool holder 59 by using a T-shaped template (not shown). The surgeon will rotate the crank handle 35 (FIG. 2) to extend clevis 29 to a desired orientation. In that orientation, probe tip 67 will be touchingpattern 25, cuttingtool 69 will be touchingbone 19, andclevis bracket 37 will be oriented approximately parallel to Y-axis 16.

The surgeon will turn on cuttingtool 69 to begin resectingbone 19. The surgeon will trace probe tip 67 over all portions of the contour ofpattern 25. The

parallel bars

41, 55 will allow thetool holder 59 to rotate freely in a plane parallel to the planes containing the

parallel bars

41, 55. Theclevis bracket 37 will allow thetool holder 59 to rotate about clevisbracket pin 39 in Z-axis directions. This provides three-dimensional movement. The

parallel bars

41, 55, however, construct thetool holder 59 such that thetool holder 59 will always be parallel to the X-axis 14. This assures that the section on thebone 19 will precisely match thepattern 25. Once completed, the surgeon will removedonor bone 19 and implant it in the patient.

FIG. 4 illustrates an alternate embodiment. The resecting replicator is the same in most of its components, therefore these will not be discussed. It differs in that thepattern 75 will be a pattern based on a prosthesis to be installed in the patient. In this case, thigh support 77 will support thethigh 79 of the patient. The patient'sfemur 81 will be exposed. The surgeon will resect the patient'sfemur 81 so as to matchpattern 75, which matches a tibial plateau to be installed. The tibial plateau is a prostheses.

FIGS. 5-7 show a third embodiment, which performs the same functions as replicator 11 of FIGS. 1-3, but has more adjustability.Replicator 83 has a frame that includes abase plate 85.Base plate 85 will rest on a table in the operating room. A pair ofslides 87, which are smooth, cylindrical bars, are mounted tobase plate 85.Slides 87 are oriented along a Z-axis. Aplatform 89 mounts slidably to slides 87. An adjustingscrew 91 will secureplatform 89 in a desired position relative tobase plate 85.

Abone holder post 93 mounts toplatform 89. Bone holder post 93 is adjustable in three dimensions, as illustrated in FIG. 7. Bone holder post 93 includes alower ball 95 andsocket 97.Ball 95 can move rotatably insocket 97 to allow orientation in three dimensions. Adjustingscrew 99 will secureball 95 in a desired position. Anintermediate ball 101 connects toball 95 by astem 102.Ball 101 locates in asocket 103. It too can be adjusted in three dimensions by means of an adjustingscrew 105. Anupper ball 107 connects tosocket 103 by astem 108.Ball 107 locates in asocket 109. An adjusting screw 111 will securesocket 109 in a desired position relative toball 107.

Astationary plate 113 mounts tosocket 109. Arotatable plate 115 mounts rotatably tostationary plate 113. An adjustingscrew 117 will lockrotating plate 115 in a desired position. Referring to FIG. 5, the forward face ofrotating plate 115 has a large number of screw holes 119. Three ormore studs 121 can be secured to any of the screw holes 119. At least one of thestuds 121 supports ascrew clamp 123 which engages adonor bone 125.Screw clamp 123 and two of theother studs 121 will secure thedonor bone 125 in a desired orientation.

A pair ofslides 127 are mounted onplatform 89 perpendicular to slides 87. Apattern post 129 mounts slidably to slides 127. An adjustingscrew 131 allowspattern post 129 to be positioned at desired points along slides 127.Pattern post 129 is of a telescoping type, having anupper section 135 which telescopes upward from a lower section. An adjustingscrew 137 will adjust the overall height ofpattern post 129.

Apattern holder 139 mounts to theupper section 135 ofpattern post 129.Pattern holder 139 has a plurality ofholes 141 on its face to enhance the adherence of a clay-like mold (not shown) placed thereon.Pattern holder 139 is a disk, slightly convex on its face.Pattern holder 139 is mounted to astem 140 that extends slidingly through the pattern postupper section 135. An adjustingscrew 142 will securestem 140 in a desired position.Stem 140 intersects pattern postupper section 135 at about a 45 degree angle.Slides 127, upperpattern post section 135, and stem 140 allow adjustment ofpattern holder 139 in three dimensions.

A pair ofslides 143 are mounted tobase plate 85 perpendicular to slides 87. Atool holder post 145 mounts toslides 143. An adjustingscrew 147 will allowtool holder post 145 to slide and be tightened to a selected position along slides 143.

The remaining portions ofreplicator 83 are the same as in the embodiment of FIGS. 1-4, thus will not be discussed in as much detail. These remaining portions include a clevis bracket 149 that mounts pivotally to the upper end oftool holder post 145. A pair of frameparallel bars 151 pivotally mount to clevis bracket 149. A pair of tool holderparallel bars 153 pivotally connect to the frameparallel bars 151 by means of alinkage plate 155. Atool holder 157 mounts pivotally to tool holderparallel bars 153. Aprobe 159 mounts to one side oftool holder 157. Acutting tool 161 mounts to the opposite side oftool holder 157.

Replicator 83 operates in the same manner as replicator 11 of FIGS. 1-3. A T-shaped template (not shown) will be employed to make sure that the tip of cuttingtool 161 is aligned with the tip ofprobe 159 along an axis that is parallel to slides 143. The surgeon will adjust the various adjusting screws of thebone holder post 93 and pattern post 129 so that centerlines ofbone holder plate 115 andpattern holder 139 will be the same distance apart as the distance betweencutting tool 161 andprobe 159. The centerlines ofbone holder 115 andpattern holder 139 will be on a bone-pattern axis that is parallel withslides 143. The Z-direction distance, which is the distance parallel toslides 87, is adjusted by movingplatform 89 along slides 87. The surgeon will trace probe 159 over the mold (not shown) while resecting thedonor bone 125.

The invention has significant advantages. The four bar linkage allows a user to trace on a pattern to assure that the resecting will match that of the pattern. This reduces the amount of resection required It also will be easier to operate than relying on skill of a surgeon using visual comparisons.

While the invention has been shown in only two of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.

Claims

We claim:

1. An apparatus for resecting a bone into a desired shape, comprising in combination:

a frame having an x-axis, a y-axis, and a z-axis;

pattern holder means on the frame for holding a pattern representing the desired shape of the bone;

bone holder means on the frame for holding the bone to be resected on the frame, the bone holder means being spaced apart from the pattern holder means along the x-axis;

a tool holder having a tool holder axis;

probe means mounted rigidly to the tool holder and having a tip for tracing over the contour of the pattern;

cutting tool means mounted rigidly to the tool holder and having a tip for resecting the bone in a contour that is the same as the pattern while the probe means is traced over the pattern;

the tips of the probe means and the cutting tool means being located on a line parallel to the tool holder axis;

rotation means for rotating the probe means and the cutting tool means about the tool holder axis; and

linkage means mounting the tool holder to the frame for allowing an operator to freely move the tool holder in three dimensions while maintaining the tool holder axis parallel to the x-axis.

2. The apparatus according to claim wherein the linkage means comprises:

a four bar linkage assembly having two pairs of parallel bars mounted between the frame and the tool holder.

3. The apparatus according to claim wherein the linkage means comprises:

a plate;

a first pair of parallel bars, each having one end pivotally mounted to the tool holder and another end pivotally mounted to the plate; and

a second pair of parallel bars, each having one end pivotally carried by the frame and another end pivotally mounted to the plate so as to position the first and second pairs of parallel bars in parallel planes.

4. The apparatus according to claim wherein the linkage means comprises:

a plate having four pivot pins equally spaced in a circumferential array 90 degrees apart from each other;

a first pair of parallel bars, each having a tool holder end and a plate end, the tool holder ends being pivotally mounted to the tool holder, the plate ends being pivotally mounted to two of the pivot pins of the plate which are spaced 180 degrees apart from each other; and

a second pair of parallel bars, each having a frame end and a plate end, the frame ends being pivotally carried by the frame, the plate ends being pivotally mounted to two of the pivot pins of the plate which are spaced 180 degrees apart from each other, so as to position the first and second pairs of parallel bars in parallel planes.

5. The apparatus according to claim 1 wherein the linkage means comprises:

a clevis carried by the frame, the clevis having a nonrotatable portion and a rotatable portion which rotates about a clevis axis which is parallel to the x-axis;

a second pair of parallel bars, each having a frame end and a plate end, the frame ends being pivotally carried by the rotatable portion of the clevis, the plate ends being pivotally mounted to two of the pivot pins of the plate which are spaced 180 degrees apart from each other, so as to position the first and second pairs of parallel bars in parallel planes, wherein the pivotally mounted ends of the first and second pairs of parallel bars allow rotation of the tool holder in planes parallel to the planes containing the parallel bars, and wherein the rotatable portion of the clevis allows movement of the tool holder in z-axis directions.

6. The apparatus according to claim 1 wherein the linkage means comprises:

a clevis carried by the frame, the clevis having a support and a rotatable bracket which rotates relative to the support about a clevis axis which is parallel to the x-axis, the bracket having two spaced apart pivot pins which are spaced apart from each other along a line perpendicular to the clevis axis;

a plate having a zero degree pivot pin, a 90 degree pivot pin, a 180 degree pivot pin, and a 270 degree pivot pin, the pivot pins being equally spaced in a circumferential array 90 degrees apart from each other;

a pair of tool holder parallel bars, each having a tool holder end and a plate end, the tool holder ends being pivotally mounted to the tool holder, the plate ends being pivotally mounted to the 90 degree and 270 pivot pins of the plate;

a pair of frame parallel bars, each having a frame end and a plate end, the frame ends being pivotally carried by the pivot pins of the bracket of the clevis, the plate ends being pivotally mounted to the zero degree and 180 degree pivot pins of the plate, wherein the pivotally mounted ends of the tool holder and frame parallel bars allow rotation of the tool holder in planes parallel to planes containing the parallel bars, and wherein the bracket of the clevis allows movement of the tool holder in z-axis directions; and wherein the apparatus further comprises

means for moving the bone holder means and the support of the clevis apart and toward each other along a line that is parallel to the z-axis to selectively position the bone holder means relative to the tool holder means.

7. The apparatus according to claim wherein the frame comprises:

a base plate;

a bone holder post supported on and extending from the base plate for supporting the bone holder means;

a pattern holder post supported on and extending from the base plate for supporting the pattern holder means; and

a tool holder post supported on and extending from the base plate for supporting the linkage means and the tool holder means.

8. The apparatus according to claim wherein the frame comprises:

a base plate;

adjusting means in the bone holder post for allowing selective positioning of the bone holder means in x, y, and z dimensions;

a pattern holder post supported on and extending from the base plate for supporting the pattern holder post;

adjusting means in the pattern holder post for allowing selective positioning of the pattern holder means in at least x and y directions; and

9. An apparatus for resecting a bone into a desired shape, comprising in combination:

a frame;

pattern holder means carried on the frame for holding a pattern representing the desired shape of the bone;

bone holder means carried on the frame for holding the bone to be resected on the frame, the bone holder means being spaced apart from the pattern holder means a selected distance along an bone-pattern axis;

a tool holder having a tool holder axis, the tool holder having a sleeve member and an extension member mounted rotatably to the sleeve member, the extension member being located on a tool holder axis and being rotatable relative to the sleeve member on the tool holder axis;

a probe mounted rigidly to the tool holder extension member and having a tip for tracing over the contour of the pattern;

a cutting tool mounted rigidly to the tool holder extension member and having a tip for resecting the bone in a contour that is the same as the pattern while the probe is traced over the pattern, the cutting tool being spaced apart from the probe the same distance as between the pattern holder means and the bone holder means;

a pair of tool holder parallel bars carried in a plane, the tool holder parallel bars being pivotally mounted to the tool holder sleeve member so as to allow movement of the tool holder sleeve member in a plane parallel to the plane containing the first pair of parallel bars;

a pair of frame parallel bars carried in a plane;

means for carrying the frame parallel bars with the frame for allowing the second pair of parallel bars to rotate in the plane containing the second pair of parallel bars and also to rotate in a direction perpendicular to the plane containing the second pair of parallel bars; and

means for connecting the two pairs of parallel bars together so as to maintain the two pairs of parallel bars in parallel planes and so as to allow the two pairs of parallel bars to rotate in said parallel planes.

10. The apparatus according to claim 9 wherein the means for carrying the second pair of parallel bars with the frame comprises:

a clevis carried by the frame, the clevis having a support and a rotatable bracket which rotates relative to the support about a clevis axis which is parallel to the bone-pattern axis, the bracket having two spaced apart pivot pins which are spaced apart from each other along a line perpendicular to the clevis axis, the frame parallel bars being pivotally mounted to the pivot pins; and

means for moving the bone support means and the support of the clevis toward and away from each other to selectively position the tool holder relative to the bone holder means.

11. The apparatus according to claim 10 wherein the means for connecting the two pairs of parallel bars together comprises:

a plate having four pivot pins equally spaced in a circumferential array 90 degrees apart from each other, each of the parallel bars being mounted to one of the pivot pins.

12. The apparatus according to claim 9 wherein the frame comprises:

a base plate;

a pattern holder post supported on and extending from the base plate for supporting the pattern holder post; and

13. The apparatus according to claim 9 wherein the frame comprises:

a base plate;

adjusting means in the bone holder post for allowing selective positioning of the bone holder means in at least two dimensions;

adjusting means in the pattern holder post for allowing selective positioning of the pattern holder means in at least two directions; and

14. An apparatus for resecting a bone into a desired shape, comprising in combination:

a frame;

bone holder means carried on the frame for holding the bone to be resected on the frame, the bone holder means being spaced apart from the pattern holder means a selected distance along a bone-pattern axis;

a cutting tool mounted rigidly to the tool holder extension member and having a tip for resecting the bone in a contour that is the same as the pattern as the probe is traced over the pattern, the cutting tool being spaced apart from the probe the same distance as between a centerline of the pattern holder means and a centerline of the bone holder means;

a clevis carried by the frame, the clevis having a nonrotatable support and a rotatable bracket which rotates relative to the support about a clevis axis which is parallel to the bone-pattern axis, the bracket having two spaced apart pivot pins which are spaced apart from each other along a line perpendicular to the clevis axis;

a pair of tool holder parallel bars, each having a tool holder end and a plate end, the tool holder ends being pivotally mounted to the tool holder sleeve member, the plate ends being pivotally mounted to the 90 degree and 270 pivot pins of the plate;

a pair of frame parallel bars, each having a frame end and a plate end, the frame ends being pivotally carried by the pivot pins of the bracket of the clevis, the plate ends being pivotally mounted to the zero degree and 180 degree pivot pins of the plate, wherein the pivotally mounted ends of the tool holder and frame parallel bars allow rotation of the tool holder in planes parallel to planes containing the parallel bars, and wherein the bracket of the clevis allows movement of the tool holder in directions perpendicular to the bone-pattern axis directions; and

extension means for moving the bone holder means and the clevis toward and apart from each other to selectively position the tool holder relative to the bone holder means.

15. The apparatus according to claim 14 wherein the frame comprises:

a base plate;

a tool holder post supported on and extending from the base plate for supporting the linkage means and the tool holder means: and wherein the extension means comprises:

a pair of slides mounted on the base plate perpendicular to the bone-pattern axis;

a platform carried on the slides for selective movement relative to the base plate; and

means for mounting at least one of the posts on the platform to allow selective positioning of said post.

16. A method for resecting a bone into a desired shape, comprising in combination:

mounting a pattern holder and a bone holder to a frame, each of the pattern holder and bone holder having centerlines a selected distance apart from each other along an bone-pattern axis;

securing a pattern to the pattern holder representing the desired shape of the bone;

securing the bone in the bone holder;

mounting a probe and a power driven cutting tool in a tool holder, positioning the tip of the probe and the tip of the cutting tool the same distance apart from each other as the centerlines of the pattern holder and bone holder, and positioning the tips on a line that is parallel to the bone-pattern axis;

mounting the tool holder to the frame with a linkage assembly which allows an operator to freely move the tool holder in three dimensions while maintaining the tips of the probe and the cutting tool parallel to the bone-pattern axis; then

operating the cutting tool while tracing the contour of the pattern with the probe to resect the bone in a configuration matching the pattern.